Integrated management of the Upper Mersey river basin using the SMILE object-oriented software system

Area of Science:

• Environmental Science
• Water Resource Management
• River Ecology

Background:

• The Upper Mersey river catchment faces challenges in managing water flows and quality.
• Assessing the impact of human activities like abstractions and discharges on riverine ecosystems is crucial.

Purpose of the Study:

• To apply the object-oriented SMILE framework for integrated management of river flows and water quality.
• To quantify the impact of various factors on low river flows and assess water quality compliance.
• To identify non-compliant discharge points and propose revisions to consent limits.

Main Methods:

• Estimation of design river flows (95% exceedance) using alternative methods.
• Quantification of influences from compensation reservoirs, surface-water abstractions, and continuous discharges.
• Classification of monitored river water quality using the River Ecosystem scheme.
• Assessment of sewage treatment works and trade effluents compliance with discharge consents.
• Monte Carlo simulations to evaluate effluent impacts on water quality variations.
• Identification of points failing proposed River Quality Objectives.

Main Results:

• The study quantifies the impact of reservoirs, abstractions, and discharges on low river flows.
• River water quality is classified, and compliance with discharge consents is assessed.
• Monte Carlo simulations reveal critical discharge points affecting downstream water quality.
• Specific locations where water quality fails to meet objectives are pinpointed.

Conclusions:

• The SMILE framework provides a robust tool for managing river flows and water quality.
• Effluent discharges significantly impact river water quality, necessitating careful management.
• Recommendations are made for revising consent limits, particularly for BOD and total ammonia, to improve water quality.